Why did so many Jews at Pentecost believe Jesus was the Messiah and expect the kingdom to come right away?
On Pentecost and after, Peter and the eleven preached that Jesus was the Messiah, and many Jews believed. Their expectation was immediate because, as soon as Israel believed, the King would come and the Kingdom would be set up. They therefore treated the coming Kingdom as just over the horizon.
Les explains that Peter and the eleven preached at Pentecost, and many Jews believed Jesus was the Messiah. They understood that once Israel believed, the King would come, so the Kingdom was imminent. Because of this, they did not return to Babylon, Rome, Spain, or North Africa; instead they stayed in Jerusalem and lived from the common kitty as a stopgap until the King came and the Kingdom was established. But Israel did not respond, the King did not come, and the kitty ran dry. They ended up poor, having sold their goods, unable to buy a ticket home. God is just, however; because they had believed the Gospel of the Kingdom, He would take care of them until natural death, through the agreement Paul made with Peter, James, and John to remember the poor saints in Jerusalem.